Ok, I deleted EVERYTHING, all drivers and previous programs and got it going. It knows the ecu is there. I have a 551 AA ecu, I tried writing both the original 551 AA and the 551 R I found here on the site. I figured out that I needed to use one of the memory layout .xml files located in the nefmoto folder. Not really sure which one to use. Just chose one that would seem to allow the flash process to start. I tried multiple times and the process starts for what seems to be a LONG time and freezes and kicks me out at about 13-14%. It says I need to reconnect and restart flashing. Tried that but it doesn't work. Anyone can tell me what I may be doing wrong?

Unfortunately I'm so frustrated, I'm about ready to give up. I haven't even been able to do a full stock flash and I'm packing it up.

I tried uninstalling and reinstalling both cables multiple times. I've tried the VCP drivers from ross tech with all the suggested settings. No matter what I do, nefmoto does not want to talk to the ross tech cable.

I reinstalled the drivers for the FTDI cable and it's recognized by nefmoto. I do slow init connect and I select the 57600 baud speed but after it connects, at the bottom it says it's talking at the higher speed. I downloaded the SAI delete 551R bin with the layout you told me, even though I don't have sai delete, just to see if it will do a full write, but I don't think it will. It's working right now.

It seems like a communication issue but is it possible it could be the ecu stopping the session at 14%? It does have the P0601 code and it was touched by APR, although they said it was programmed back to my stock file. Just really frustrated and disappointed right now.

Desolder the chip, flash it in programmer, re-solder.
Or Galletto in boot mode on bench.

Encouragement to jump off a cliff is maybe not such a good thing...

For power supply, a car battery works well if where your car is parked is close enough to your workstation (or don't mind hauling it there).  It really is the perfect source. Then you just need the correct length of wire (heavy enough not so there isn't much voltage drop) and away you go.  For test clips, on the ECU side the wires that come with the Pomona test clip I mentioned previously have connectors that are perfect (if you are thinking of doing Immo Off).  For the cable side, standard female spade connectors work for main power and ground, and salvaged PC power supply connectors (cut apart) are a kludge but work.

I have yet to get the 551S or AA into boot mode, using all of the posted tricks.  I'm hopeful you do, then you can share!

Some people have had luck getting the S (should be the same as the AA) into boot mode, but it seems really finicky.  Recent comments suggest that voltage should be "just right", not too high (i.e. battery not on charger, but fully charged with no other loads whatsoever).  I haven't tried since learning this (I've always tried with battery on charger.)  May be why I've not had luck.

If you pick up an R box it will work fine (you will be down 15 hp in power) but you still will have to deal with Immo.  The APB-BEL engine designation break was in 2003 (maybe mid-2002?), so the ECU from an earlier car will not work.  Applying Immo-off to your R box using the EEPROM reader/writer and test clip I supplied the link for earlier may be your quickest route.

You can boot mode with the ECU in-car (over OBD) by opening up the back with the ECU near its usual resting place, or you can boot mode on the bench, but I don;t see how you can boot mode on the bench and then transfer the ECU to the car and complete the process.

Because you can flash a stock file in boot mode, and then you can use nefmoto to flash over that to clear the code.